Microchips having a micro-channel are beginning to be used for automatic analyzing devices that analyze blood samples, urine samples, and the like. In such a microchip, a reagent, including a buffer (buffer fluid), is injected in a micro-channel by a probe and then a high voltage is applied to the micro-channel. The application of the high voltage causes each composition component of the sample in the channel to be migrated, and a target substance for measurement in the sample is separated by the difference in the degree of migration. The target substance separated is identified by the reagent and detected in a detection section of the analyzing device. A series of these processes is performed automatically in the analyzing device.
In the mean time, it is often the case that one analyzing item, for example, the analysis of a particular protein requires a plurality of different reagents. These reagents are provided in reagent containers in advance, and a plurality of reagent containers is disposed in an analyzing device. Under the circumstances described above, it is desired that analyzing devices may include therein many reagent containers by downsizing the containers for efficient analysis. A typical reagent container has an opening for inserting a probe, but the opening is normally covered with a screw cap to seal the inside. When using such type of reagent container, the cap is manually removed and then the reagent is mounted in an analyzing device.
Further, a method of piercing a screw cap by a pipette for sucking a reagent without manually removing the screw cap is also known as described, for example, in Japanese Unexamined Patent Publication No. 5 (1993)-099931. In the conventional method described in the aforementioned patent document, a pipette is inserted into a reagent container by pushing open the tip (bottom) of an inverted conically shaped cap with the tip of the pipette moved downward. When the pipette is pulled out from the reagent container, the reagent adhered to the tip of the pipette is wiped out by the edge portion of the hole pierced in the tip of the cap.
Further, another type of conventional reagent container in which a lid having a hinge mechanism is provided on the opening of the container is also known as described, for example, in Japanese Unexamined Patent Publication No. 2004-156971. Such a reagent container is designed, after being mounted in an analyzing device, to automatically open/close the lid by the hinge mechanism in cooperation with a mechanism provided in the analyzing device.
In the typical reagent container having a screw cap described above, the cap size is greater than the opening size of the reagent container so that it has been difficult to closely pack a plurality of reagent holding sections in one reagent container. Further, even when the amount of a reagent to be held is very small, it has been difficult to downsize the reagent container because of a limitation in downsizing the cap. Further, it has been necessary to individually open the caps one by one, requiring the time and effort if there are many caps to be opened. Still further, it has been difficult for a reagent container holding a plurality of types of reagents to hold the reagents in a balanced manner in which, depending on the type of reagents, volume of reagent decreases when required amount is small and volume of reagent increases when required amount is large.
In the reagent container described in Japanese Unexamined Patent Publication No. 5 (1993)-099931, a sufficient strength is required for the pipette to pierce a synthetic resin cap. It is difficult, however, to expect the pipette to have a sufficient strength to pierce the cap because the pipette is used for accurately handling a minuscule amount of a liquid reagent and therefore needs to be as thin as possible in order to reduce the adherence of the reagent other than the amount to be sucked. Further, when the pipette is pulled out of the cap after sucking a reagent, the pipette is wiped by the pierced hole so that the liquid is adhered around the hole in the cap. The adherence of the liquid to the cap may lead to an erroneous detection of the liquid level of the reagent when detected by a capacitance measurement. That is, there may be a case in which the pipette would have been erroneously judged to reach the liquid level when the pipette contacted the liquid around the hole, causing it difficult to perform accurate liquid level detection repeatedly. Further, the reagent adheres to a portion of the pipette other than the tip when the pipette passes through the pierced hole of the cap adhered with the liquid, whereby the pipette is contaminated with the reagent to an upper portion of the tip that actually contacts the liquid level of the reagent. Generally, the tip of a pipette is cleaned with water or the like each time the sucking is performed to reduce the residual amount of the reagent to a predetermined amount, if a larger pipette portion contacts the liquid, the more area needs to be cleaned, posing a problem that more time and effort is required for the maintenance.
In the reagent container disclosed in Japanese Unexamined Patent Publication No. 2004-156971, it is difficult to closely pack a plurality of reagent holding sections in one reagent container because the container needs to be provided with a bulky hinge mechanism. In addition, a mechanism for opening/closing the hinge mechanism needs to be provided in the analyzing device, resulting in that the analyzing device becomes complicated in structure and expensive.
The present invention has been developed in view of the circumstances described above, and it is an object of the present invention to provide a reagent container capable of holding a plurality of reagents therein and yet reduced size.
It is a further object of the present invention to provide a reagent container that allows easy opening, i.e., easy piercing.
It is another object of the present invention to provide a reagent container that does not require a strong probe.
It is still another object of the present invention to provide a reagent container capable of reducing contamination of a probe and the like by a sample.
It is a further object of the present invention to provide a reagent container that constantly allows accurate liquid level detection by a general capacitance measurement.